Genetically Modified Foods, nothing to fear

Genetically modified crops (GMs or GMOs for genetically modified organisms) have existed for thousands of years, but now that we know how to splice genes in the laboratory, there is concern over food safety.  Much of that concern is unwarranted.  Nevertheless, there are campaigns to require product labeling when some foodstuffs contain GMOs. (See a story about such a campaign in Tucson here.) The food industry is generally against that requirement for two reasons: 1) it implies that the produce is somehow inferior to non-modified foods, and 2) costs; it could require companies to have separate processing lines for GMO and non-GMO foods.

The American Association for the Advancement of Science has a statement on GMOs and labeling which begins:

“There are several current efforts to require labeling of foods containing products derived from genetically modified crop plants, commonly known as GM crops or GMOs. These efforts are not driven by evidence that GM foods are actually dangerous. Indeed, the science is quite clear: crop improvement by the modern molecular techniques of biotechnology is safe. Rather, these initiatives are driven by a variety of factors, ranging from the persistent perception that such foods are somehow “unnatural” and potentially dangerous to the desire to gain competitive advantage by legislating attachment of a label meant to alarm. Another misconception used as a rationale for labeling is that GM crops are untested.”

See full statement here.

Humans have been genetically modifying food crops for a long time.  Ever hear of teosinte?  It is a grass that grows in Mexico and Central America.  Many thousands of years ago, farmers began selecting the seeds from certain individual teosinte plants that favored larger seeds or kernels and planted these larger seeds to encourage the trait.  This process is known as selective breeding or artificial selection. Eventually the plant became known as maize (corn).  The maize or corn cob looks nothing like the original plant but, according to the University of Utah, “at the DNA level, the two are surprisingly alike. They have the same number of chromosomes and a remarkably similar arrangement of genes. In fact, teosinte can cross-breed with modern maize varieties to form maize-teosinte hybrids that can go on to reproduce naturally.”

Beginning in the 1950s, Norman Borlaug, so-called father of the Green Revolution, took selective breeding to new heights.  His work helped save millions of lives.  An article in Forbes Magazine recounts the story:

“First, he and his colleagues laboriously crossbred thousands of wheat varieties from around the world to produce some new ones with resistance to rust, a destructive plant pest; this raised yields 20% to 40%.

“Second, he crafted so-called dwarf wheat varieties, which were smaller than the old shoulder-high varieties that bent in the wind and touched the ground (thereby becoming unharvestable); the new waist or knee-high dwarfs stayed erect and held up huge loads of grain.  The yields were boosted even further.

“Third, he devised an ingenious technique called “shuttle breeding”– growing two successive plantings each year, instead of the usual one, in different regions of Mexico.  The availability of two test generations of wheat each year cut by half the years required for breeding new varieties.  Moreover, because the two regions possessed distinctly different climatic conditions, the resulting new early-maturing, rust-resistant varieties were broadly adapted to many latitudes, altitudes and soil types.  This wide adaptability, which flew in the face of agricultural orthodoxy, proved invaluable, and Mexican wheat yields skyrocketed.”

As a result, Mexico became an exporter of wheat and India and Pakistan doubled their production.

Borlaug’s work also led to the development of high-yield rice, including vitamin-A-rich “golden rice” in Asia.

Advances in molecular biology allow gene splicing to produce GMOs faster than the older method of selective breeding.  Is this unnatural?  I suppose that strictly speaking it is, but it just continues a process that we have been using for thousands of years.  Modern gene splicing makes it easier to create crops with desirable characteristics and also easier to make sure undesirable traits are prevented or eliminated.

GMOs have been a controversial topic in the European Union.  Last year, however, the European Commission’s Chief Scientific Advisor said “Genetically modified organisms (GMOs) are no riskier than their conventionally farmed equivalents…There is no substantiated case of any adverse impact on human health, animal health or environmental health, so that’s pretty robust evidence, and I would be confident in saying that there is no more risk in eating GMO food than eating conventionally farmed food.”

Professor Alan McHughen, a plant molecular geneticist at UC Riverside wrote a book called “Pandora’s Picnic Basket: The Potential and Hazards of Genetically Modified Foods” in which he reviews the fears and facts surrounding GMOs.. McHughen is generally in favor of GMOs.  In a recent article he claims:

“GMO technologies have been around since the early 1970s and have given us many useful products, from human insulin to safer crops grown with fewer pesticides. Moreover, in over 30 years of experience, according to authoritative sources such as the U.S. National Academies and the American Medical Association, there is not one documented case of harm to humans, animals or the environment from GM products.”

McHughen does note that  “Recently, French scientist Gilles-Éric Séralini and his team published a peer-reviewed paper that claimed harm to test animals after they were fed GM corn for two years.”

Andrew Revkin of the New York Times writes of that study here.  The study claimed to find big impacts on longevity and cancer rates in rats fed Roundup-ready corn.  Revkin notes some red-flags in the study: “One issue is that, while the experiments ran for two years, far longer than most rat studies of food safety, the chosen rat breed commonly develops tumors after two years. Combined with small sample size (the different test groups had 20 animals each), this has led even some advocates for GMO labeling to question the results….Another red flag was that tumor rates didn’t increase in line with the dose of GMOs fed to animals, as scientists would expect to see if the genetically engineered corn were to blame…”

A study reported in Food and Chemical Toxicology, April, 2012, examined 12 long-term projects and 12 multi-generational studies of the effects of diets containing GM maize, potato, soybean, rice, or triticale (a hybrid of wheat and rye) on animal health.  ” Results from all the 24 studies do not suggest any health hazards and, in general, there were no statistically significant differences within parameters observed.”

One oft cited concern is allergic reaction to food.  Gene modification involves substituting or adding a protein, and almost any protein can be an allergen.  If you do an internet search of “GMO” and “allergies” you will find thousands of sites expressing concern but almost none providing any clinical evidence of GMO-caused allergies.  When American-grown Starlink corn was first introduced into the UK, many people claimed asthma symptoms worsened.  The CDC investigated but could not find a link.  GMO soybeans have also been accused of causing allergies.  A Korean clinical study found no difference in reactions to GMO and non-GMO soybeans.  Ironically, I saw that there are some attempts to reduce food allergies, such as to peanuts, through genetic modification. By law, if a new protein trait has been added, the protein must be shown to be neither toxic nor allergenic.

As far as I can tell, there are no significant health safety issues associated with GMO foods.  Calls for labeling such as the one reportedrecently in the Arizona Daily Star seem to be based on ignorance and fear rather than evidence.  If, however, there is some real proof that certain GMO foods cause adverse effects (like peanuts allergies), then such products should be labeled. We have been using GMO foods for a long time and, so far, no such danger has been identified.

For more information see an article by molecular biologist Michael Eisen “How Bt Corn And Roundup Ready Soy Work – And Why They Should Not Scare You.”  He writes: “Approximately 90% of soybeans, maize, cotton and sugar beets grown in the US are have been genetically modified to produce a protein that kills common insect pests or to make them highly tolerant of an herbicide used to control weeds, or in some cases both. To make a rational judgment about whether these specific GMOs are good or bad, it’s important to understand exactly what they are and how they work.”  He also notes that use of GMOs has greatly reduced the need for pesticides. See the rest of his article here.

Please take note: This post is about food safety and does not address the separate issue of possible cross-pollination from GMO crops, an issue of great economic concern to organic farmers.  However, I will mention that there are methods to minimize or prevent cross-pollination as discussed by the University of Minnesota here and the University of Arizona here. Organic farmers can also use GMO-resistant strains. For instance, a new lineage of organic corn hybrids, known as PuraMaize®, seek to end the battle of GMO corn contamination. Using a natural gene blocking system, these organic hybrids are able to prevent fertilization of foreign GMO and colored corn varieties.


  1. It’s not true that there is no harm; myriad studies have shown this. Please do your research and give serious thought to ideas you may not agree with. I will seek out non-GMO foods, and I hope other people will do the same. For those who believe these foods are just fine, then shopping will be easier and cheapter for them. In the meantime, tampering with our food supply should not be allowed, period. This is about money, not about feeding a hungry planet as they say or about the health of humans. It’s about money!

    1. Please give citations and links to some of those “myriad” of studies to back up your claim. I could not find any clinical evidence of harm, just unverified anecdotal stories.

      1. “Nation of Change” an online compilation of articles, runs pieces often on studies that have been done showing harm from GMO feed.
        No one is asking food producers to stop using GMOs or to run two lines for processing. They can do exactly what they’re doing now; they just need to tell us about it. It’s only fair. High fructose corn syrup, trans fats, calories, etc. are all listed. If companies fear people won’t buy their foods if they admit to using GMOs, then that tells you something too. Hiding it is going to result in people going past the law and looking for labels that say “non-GMO.” Whole Foods is expanding its line of non-GMO offerings; maybe other stores will do the same. In the future, more companies may voluntarily eliminate GMO.

    1. I just saw that story today. That one may be a case of cross-pollination that got away or seeds got mixed up. The story says “There is no scientific evidence that suggests GM wheat is unfit for consumption.”

      1. “There is no scientific evidence that suggests GM wheat is unfit for consumption” because it takes years to research and test the effect of GM foods on the human body. And Korea joined Japan in banning US wheat imports, driving down Monsanto shares 4% – there is justice after all.
        Nothing to fear – except the loss of one of our biggest exports.

  2. This writing appears to be nothing more than a generic assemblage of hackneyed talking points as if programmed into a blog bot from a Monsanto PR sell sheet. The bottom line is that there is nary one nutritional benefit for GMOs. Nary a one!

    Take a look at the differences between organic and GMO corn:

    • Organic corn has 14 ppm of manganese. GMO corn has only 2 ppm.

    • Real corn has 7 times more manganese!

    • Organic corn has 6130 ppm of calcium. GMO is stripped down to 14 ppm.

    • Real corn has 437 times more calcium!

    • Organic corn has 113 ppm of magnesium. GMO corn is vacant, with only 2 ppm.

    • Real corn has 56 times more magnesium!

    If that is NOT enough for you…

    Scientists Discover Bt Toxins Found In Monsanto Crops Damage Red Blood Cells



    New Study Links GMO Food To Leukemia


    I have over four-dozen more links showing that GMOs serve nary one noble purpose as well as irrefutable evidence from farmers proving that GMO crops yield far less product. But I would rather just point out the obvious. There is a growing myriad of justifiable reasons why GMOs are being rejected by other countries as well as the US consumer. According to Google, GMO trending hit an all-time high this week. Clearly, you have missed the entire point on this GMO issue. Consumers have a right to make informed decisions for buying food for their families. Over five different polls show that over 90% of Americans are in favor of GMO labeling. Yet, John McCain chose to ignore what 90% of his constituents want. Yeah Monsanto spends money corrupting our government. Big money. This is what is wrong with our media. One-sided, abounding with baseless claims, biotech propaganda, soulless shills and invidious, hack writers being given a forum to confuse the public.

    [By the way, your attempts at trying to spin the GMO issue into one that cross-breeding and GMOs have been around for a long time. Bt corn with a built-in pesticide that cannot be washed off was first commercialized in the mid-90s! Show me one nutritional benefit of bt corn. You won’t find one.]

    1. Update, Marko, did your actually read your links? Your second link rebuts the first one.

  3. I’ve been doing research for 30 years, I’m a PhD from Stanford, and I’m in the medical field.

    Lack of strong, obvious adverse effects from lessor degrees of genetic modification does not constitute evidence that greater degrees of genetic modification are safe, nor is it evidence that future genetic modifications of any degree will be safe. The author is misrepresenting science.

    Also, a lack of evidence of adverse effects does not prove ANYTHING is safe. It can mean that we just haven’t learned how to detect all the effects of genetic modification yet. A good researcher is very humble this way: we readily admit that our scientific methods are limited. Again, the author is misrepresenting science as having proven safety.

    Hasn’t the author noticed that even highly funded medical research often produces conflicting results? And that even after millions and millions of dollars in clinical trials and FDA reviews, some drugs still get pulled off the market as having unexpected adverse effects? Why would the author think that agricultural research, which is not as well funded as medical research, somehow produces more reliable results than medical research? The author really doesn’t understand the limitations of science.

    As a personal opinion, I resent the author’s assertion that information about food sources should be withheld from the consumers who want that information. To me, deliberately withholding relevant information is both very unscientific AND undemocratic.

    1. I agree, in general, with your second and third paragraphs. Science is often uncertain. Your complaint seems to be an extreme invocation of the Precautionary Principal. And it ignores the opposite contention: GM foods have not been proven unsafe. They seem to hold the same risks as conventional food. There are always risks in life. By the way, how do you feel about electricity? Do you think that it is safe enough for widespread use?

      1. Please do not censor my post like you did the last one, and as many GMO adviocates do- I am taking a screenshot this time.
        First of all, the precautionary principle, is embedded in medicine as ” first do no harm”. Every physician in the country practices it, and you should be thankful they do-because it requires balancing risks and benefits of any intervention, including food. Additionally the review you linked doesn’t say what you think it says

        Half of the studies in this review are deficient 90 day trials in which half the rats go missing, along with crucial tests of metabolic function, are statistically skewed to increase rates of false negatives and are woefully statistically under powered.

        The rest of the studies are suggestive of medical harm.

        Maize Bt Kilic and Akay, 2008.
        Granular degeneration level in 10% of examined sections wasmaximum (level 4) in Group III
        Liver Focal infiltration Group III : 7/14 8/16
        Congestion: 10/14 7/16 Granular degeneration 9/14 13/16
        Nuclear border change 10/14 13/16
        Kidney Enlargement in parietal layer of Bowman’s capsule 6/14 5/11 Tubular degeneration 13/14 9/11

        Click to access Kilic%26Akay08BtMaizeFeedingStudy.pdf

        Fate of transgenic DNA and evaluation of metabolic effects
        in Goats fed genetically modified soybean and in their offspring
        R. Tudisco et al.
        On the contrary, in blood and milk of treated goats,
        fragments both of the 35S promoter and the CP4 EPSPS gene were detected. These fragments were also found in treated kids with significant detection of the 35S
        promoter in liver, kidney and blood, and of the CP4 EPSPS gene fragment in liver, kidney, heart and muscle. A significant increase in lactic dehydrogenase, mainly concerning the lactic dehydrogenase-1 isoenzyme was found in heart, skeletal muscle and kidney of treated kids, thus suggesting a change in the local production of the enzyme.

        Click to access 8857.pdf

        The effect of multigenerational diet containing genetically modified triticale on immune system in mice.
        M Krzyżowska, M Wincenciak, A Winnicka, A Baranowski, K Jaszczak, J Zimny, M Niemiałtowski
        The safety assessment of genetically modified (GM) food and feed is performed to identify the possible
        effects upon animal and human health, also the long-term, multigenerational influence upon functioning of different organs and systems, such as the immune system.
        In this study C57BL/6J mice were fed for five consecutive generations with pellets containing 20% of conventional triticale grain (control) vs. pellets containing 20% of the transgenic triticale grain resistant to BASTA herbicide
        (experimental). The F5 experimental animals showed enlarged inguinal and axillary lymph nodes, but not spleens, and increased WBC counts in blood (but
        within the norm for Mus musculus). Immunophenotyped cell suspensions derived from spleens, inguinal and axillary lymph nodes and PBMCs from blood showed the
        significant decrease in the percentage of T cells in spleen and lymph nodes and the B cells in lymph nodes and blood of the F5 experimental mice in comparison
        to the control F5 mice. Immunoblotting analysis of IL-2, IL-4, IL-10, IL-12, IL- 6, IFN-gamma levels in serum showed significantly increased IL-2 levels and decreased IL-6 levels in the F5-experimental mice sera. No significant changes in the levels of IgE in sera in both mice groups were observed. The obtained results indicate that multigenerational use of feeds for rodents containing the
        GM-triticale leads to expansion of the B cell compartment in the secondary lymphoid organs, but it is not caused by malignant processes or the allergic response.

        Soybean Glyphosate-tolerant soybean (CP4 EPSPS) Malatesta et al. (2002a). Ultrastructural morphetrical and immunocytochemical analyses of hepatocytes nuclei

        Irregularly shaped nuclei, higher number of nuclear pores,
        numerous small fibrillar centres and abundant dense fibrillarcomponent, nucleoplasmic and nuclear splicing factor more abundant in GM fed mice higher metabolic rate and molecular trafficking(mechanisms unknown)

        Soybean Glyphosate-tolerant soybean (CP4 EPSPS) Malatesta et al. (2003).
        Ultrastructural morphetrical and immunocytochemical analyses of pancreatic acinar cells nuclei.
        Decrease of the shape index and the fibrillar centres
        density and increase of the pore density, the perichromatin granule density, the percentage of fiibrillar
        centres in GM-fed mice. Lower Labeling for the nucleoplasmic splicing factors a diet containing significant amounts of GM food seems to influence the pancreatic

        Soybean Glyphosate-tolerant soybean (CP4 EPSPS)
        Malatesta et al. (2008).

        Histocytochemistry of hepatocytes 2 groups (n = 10 female mice); in total 20 individuals. Different expression of proteins related to hepatocyte metabolism, stress response, calcium signaling and mitochondria in Gm fed mice. Indications of reduced metabolic rate in GM-fed mice GM soybean can influence some liver features during ageing

        Moreover, preliminary EM analyses of hepatocytes and
        pancreatic acinar cells revealed smaller, irregularly shaped cell nuclei containing increased amounts of heterochromatin and perichromatin granules (ribonucleoprotein structural components involved
        in transport and/or storage of already spliced premRNA) in T lambs (Fig. 3).

        Click to access Three-yearlongitudinalstudyBt176.pdf

        Soybean Glyphosate-tolerant soybean (CP4 EPSPS)
        Vecchio et al. (2004).
        Enlarged vesicles of the smooth endoplasmic reticulum,
        Decrease in the number of nuclear pores. Reduced labeling during the 2–8 month interval. Increase in perichromatin granules in Sertoli cells and in spermatocytes of GM fed mice Atransient transcriptional decrease during the 2–8 months interval. Most of the effects reversible. Causes of the alteration not established, especially because glyphosate residues might influence transcriptional process.

        Thus it is clear to me that you either just read the abstract or you are misinforming your readers intentionally. Either way, please either do your homework, or refrain from writing on subjects you are unqualified to discuss. Misinforming readers on this subject is a terrible practice.

      2. dogctor, one of your comments was deleted because it did not conform to TC commenting guidelines. Be civil.

      3. Hi, Jonathan

        Electricity is a great example. NO responsible scientist EVER makes a blanket statement that electricity is safe. It can kill. Doesn’t every appliance we plug into a wall socket come with a warning label?

        Perhaps we differ on our definition of harm. I note that you have experience in the Army Chemical Corps testing experimental weapons and equipment. Probably your main criteria of harm was killed vs not killed. This hardly seems to qualify you to pass judgement on the safety of genetically modified foods.

        Tests of potential harm use a threshold of harm, below which some harm may still occur but it is low enough to be acceptable to the researcher. So please tell your readers — what do you think is an acceptable level of harm to them or their children?

        I compete for research funding every day, and I know how scarce those funds are. There is not enough money in the USA to test for all forms of harm. As only one example: suppose a diet consisting of 50% GMO foods consumed from age 1 to 18 were found to significantly increase the probability of being involved in domestic violence by the age of 35 (strictly a behavioral effect). Would that constitute harm in your eyes? How many highly rigorous randomized controlled trials have already been published regarding just this one specific example of potential harm? Is this one of the FDA-required tests of harm? If not, why not?

      4. You examples are absurd.
        1. Everyone know when they are flipping on the electricity, it is not hidden from them.
        2. They do no hold the same risks as conventional food. You haven’t done your homework.
        They are created by two very imprecise processes.
        1. Bombardment with high velocity particles which cause insertional mutagenesis, introducing uncontrollable number of genes ( we have never eaten in transgenic forms “EPSPS) with superfluous DNA in uncontrollable lengths, uncontrollable orientation, which leads to truncated proteins and fusion proteins.
        2. Agrobracterium transformation, which is just as imprecise. You should really look at page 4 or page 64 of the NRC, to realize that there unintended effects anticipated from risky transformation of unrelated species by both of these methods.

        Abnormal proteins can be allergenic, toxic and can kill– think of snake and bee venom: what are they? -tiny amounts of toxic proteins that indeed can result in death.
        The biggest difference is that GMO proteins do not cause acute adverse effects, like the above toxins do- about the only legitimate assurance of safety there is, is that people are not dropping dead on the street en masse from acute and peracute adverse effects. .
        Does that in any way imply that they are safe to ingest long term and don’t cause chronic diseases?
        Do we have a plethora of convincing long term safety studies in lab animals?
        No–the FDA accepts industrial studies lasting 90 days.
        Do we have any studies in people?
        We have one: it showed that EPSPS transgene was taken up by the enteric bacteria of some ileostomists.
        That’s the extent of the safety data for you.

        Are these mutant plants with their mutant proteins, sprayed with glyphosate and its toxic adjuvants, which inhibit your biochemical detoxification system in your liver (cytochrome p450) in trace amounts and alter your intestinal bacteria, lead to inflammation in gut predisposing us to inflammatory bowel disease, the prevalence rates of which is rising in kids?
        Are they raising prevalence rates of liver disease, kidney disease?….. no one has looked, and they should.

        So, the meme being passed around of no one being harmed by GMOs is a wicked lie. It is unscientific as it is based in fiction, rather than methodological or empirical data and evidence. Not looking means not finding, but in now way does not looking mean absence of chronic medical harm.

      5. From page 8 of your link: “All evidence evaluated to date indicates that unexpected and unintended compositional changes arise with all forms of genetic modification, including genetic engineering. Whether such compositional changes result in unintended health effects is dependent upon the nature of the substances altered and the biological consequences of the compounds. To date, no adverse health effects attributed to genetic engineering have been documented in the human population.”

      6. Nice job of not looking….and thus not finding.
        Please go to Pub Med and find human or animal epidemiological or empirical data in the form of prospective, retrospective studies.
        There is zip, zero, zilch…..and you are an agent of Misinformation. Proud of yourself?

  4. Please fix the following two links in the article as they appear to be broken:

    1. “(See a story about such a campaign in Tucson here.)”

    2. “Calls for labeling such as the one reported recently in the Arizona Daily Star seem to be based on ignorance and fear rather than evidence.”

  5. I’d prefer to know what I’m eating so I can make my own decisions. The problem with GMO’s is the lack of labeling and the fact that the corporations that produce these products don’t want us to know when we are eating them. I prefer to buy non-GMO products until I know that they are completely safe. Only time will tell. But it seems that you do have a bias toward the conservative/corporate agenda based on what I’ve read on your column, so therefore I cannot trust much of what you say.

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